A manufacturing process of semiconductor devices includes a peripheral portion cleaning process of removing an unnecessary film or contaminants from a peripheral portion of a semiconductor wafer (hereinafter, simply referred to as a “wafer”), which is a target substrate, by supplying a processing liquid such as a chemical liquid to the peripheral portion of the wafer while rotating the wafer. Such a cleaning is called as a bevel cleaning or an edge cleaning.
Japanese Patent Application Laid-Open No. 2012-84856 discloses a liquid processing apparatus for cleaning a peripheral portion. The liquid processing apparatus includes a vacuum chuck configured to hold a wafer horizontally and rotate the wafer around a vertical axis, a nozzle configured to eject a chemical liquid onto the peripheral portion of the rotating wafer, a cup configured to surrounds the periphery of the wafer to receive a processing liquid scattered from the wafer, and a disc-shaped cover member configured to the upper side of the upper surface of the wafer and seal the upper surface of the cup in close proximity to the upper surface. A chimney-shaped intake pipe is provided from the central portion of the upper surface of the cover member. Further, the cover member is provided with a protrusion that protrudes downward at a position just above the peripheral portion of the wafer. Since the interior space of the cup is at a negative pressure by being evacuated, a down flow of clean air flowing through a housing is sucked from the intake pipe, flows through a space between the upper surface of the wafer and the lower surface of the cover member towards the peripheral portion of the wafer, and flows through a narrow gap formed between the protruding portion of the cover member and the upper surface of the wafer into the inside of the cup. By this gas flow, the mist of the chemical liquid scattered towards the outside of the wafer is prevented from being attached again to the upper surface of the wafer and contaminating the upper surface of the wafer (device forming surface).
However, since the cover member of Japanese Patent Application Laid-Open No. 2012-84856 covers the entire surface of the wafer, the flow resistance from the inlet of the intake pipe to the cup is large. As a result, unless the interior space of the cup is exhausted strongly, a gas flow with a sufficient flow rate may not be obtained at the outlet of the narrow gap.